Indemnity bond to modify terms of appointment

My employer wants me to sign an indemnity bond in liue of the increment and promotion.This has not been mentioned at the time of joining(one year back).they have promised me an increment after six months but now after one year they are giving a handsome increment of 30% only when i sign indemnity agreement which is modifying terms of appointment which is the notice period has been incresed from 1 month to three month.I wanted to know that does that bond has any legal implications on me if i leave the job abrubtly after signing the bond as i need increment.Indemnity bond is made on a100 rs stamp paper.they have mentioned that in case of breach of indemnity bond i have to pay three month of salary +150000+12% tax from the date of breaching the bond.Pls tell me how can i deal with the situation as i need increment and at the same time it also dont want to get strucked with bond.I alos want to know the legal implecations on me if i break the indemnity bond.
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